Effect of Multi-Mode Thermosonication on the Microbial Inhibition and Quality Retention of Strawberry Clear Juice during Storage at Varied Temperatures

Abstract

Strawberry juice, which is rich in nutrients and charming flavor, is favored by consumers. To explore whether multi-mode thermosonication (MTS) can ensure the quality stability of strawberry clear juice (SCJ) during storage, the effects of microbial inhibition, enzyme activity, and physicochemical properties of SCJ pretreated by MTS were evaluated during storage at 4, 25, and 37 °C in comparison with thermal pretreatment (TP) at 90 °C for 1 min. The MTS, including dual-frequency energy-gathered ultrasound pretreatment (DEUP) and flat sweep-frequency dispersive ultrasound pretreatment (FSDUP), were conducted at 60 °C for 5 and 15 min, respectively. Results showed that the total phenols, flavonoids, anthocyanins, ascorbic acid, and DPPH free radical scavenging ability of SCJ decreased during the storage period. The control sample of SCJ was able to sage for only 7 days at 4 °C based on the microbiological quality, while the FSDUP and DEUP group extended the storage period up to 21 and 14 days, respectively. The polyphenol oxidase in SCJ pretreated by MTS did not reactivate during the storage period. The MTS remarkably (p < 0.05) reduced the color deterioration, browning degree, and nutrient degradation during the storage period. Moreover, the FSDUP group exhibited the maximum shelf life with a minimum loss of quality, demonstrating that it was the most suitable processing method for obtaining high-quality SCJ. It can be concluded that the MTS has the potential to inhibit enzymatic browning, inactivating microorganisms, preserve original quality attributes, and prolong the shelf life of SCJ.

Applications of ultrasonication on food enzyme inactivation- recent review report (2017–2022)

“… Reduction in the enzyme activity of PPO after TS to 12.7% while PME was reduced minimally about 93.1%. [76] Fruits (Mango and jackfruit) and rice smoothie PPO, PME Probe US; 1500 W; 20 kHz; 70–85% amplitude; 40–55 °C for 15–25 min. Highest reduction at 85% amplitude, 55 °C for 25 min.…”

“…Thus, the tissue matrix in whole fruit and vegetable commodities would also influence the inactivation efficiency. However, in liquid products such as clear juice [76] , the pulp [77] , paste [78] , and nectars [79] , [80] disregarding the consistency of the product, enzyme inactivation was efficient and predominantly depended on the process and product parameters.…”

“…Similarly, [76] investigated the effect of multimode TS on the microbial and biological quality of the strawberry clear juice with the inactivation of PPO during the storage period of 28 days at different temperatures (4 °C, 25 °C, and 37 °C). The authors exhibited the efficiency of the TS process at (60 °C; 15 min) to yield irreversible change in the enzyme activity i.e., a reduction in the residual activity of 90.7% was retained till the 28th day of storage at all the temperatures.…”

“…Such an irreversible change was also seen in cloudy apple juice for PPO inactivation at 62 °C for 20 min with 750 W probe US [81] . [76] have also parallelly studied the thermal pre-treatment effects (90 °C for 1 min) and showed that though the enzyme inactivation caused is two times higher than that of TS, other bioactive properties including total phenolics, total flavonoids, total anthocyanins, and total ascorbic acid contents are retained in the thermo-sonicated samples than in the thermally processed samples. Therefore, TS can be an efficient enzyme inactivation technology with all the biochemical constituents unaffected.…”

Comparative study on Angelica sinensis after different processing with yellow rice wine in color, aromas, chemical components, and antioxidant activities

“…After the instrument had been switched on and stabilized with a corrector, the images were obtained by evenly placing the samples on a surface dish and recording each sample's color number and ratio ( Esatbeyoglu et al, 2023 ). Each color number was expressed in terms of L* (lightness), a* (red and green values), b* (yellow and blue values), and the total color value ( Feng et al, 2022 ). Where the total color value of the sample can be expressed as E * ab by the formula E * ab = , the larger the total color value, the lighter the color.…”